Ejector design and theoretical study of R134a ejector refrigeration cycle A. Khalil a , M. Fatouh b , E. Elgendy b, * a Mechanical Power Engineering Department, Faculty of Engineering, Cairo University, Giza 12316, Egypt b Mechanical Power Engineering Department, Faculty of Engineering at El-Mattaria, Helwan University, Masaken El-Helmia P.O., Cairo 11718, Egypt article info Article history: Received 28 September 2010 Received in revised form 27 December 2010 Accepted 6 January 2011 Available online 13 January 2011 Keywords: R134a Ejector System Design Air conditioning Performance Modelling abstract In the present paper, a mathematical model is developed to design R134a ejector and to predict the performance characteristics of a vapor jet refrigeration system over a wide range of the investigated parameters. These parameters include boiling temperature (65e85  C), condensing temperature (25e40  C), evaporating temperature (0e10  C), degrees of superheat (0e15  C), nozzle efficiency (0.75e0.95) and diffuser efficiency (0.75e0.95). Simulated results showed that the present model data are in good agreement with experimental data in the literature with an average error of 6%. It is found that the ejector area ratio at boiling temperature of 85  C is about double that at boiling temperature of 65  C for various evaporating and condensing temperatures. The present results confirm that waste heat sources of temperature ranging from 65 to 85  C are adequate to operate vapor jet refrigeration system for air-conditioning applications. ª 2011 Elsevier Ltd and IIR. All rights reserved. Conception de l’e ´ jecteur et e ´ tude the ´ orique d’un cycle frigorifique au R134a a `e ´ jecteur Mots cle ´s : R134a ; e ´ jecteur ; syste ` me ; conception ; conditionnement d’air ; performance - mode ´ lisation 1. Introduction In many industrial situations, heat is rejected to the ambient at moderate temperatures (80e150  C) or at low temperatures (<80  C) whereas refrigeration and air-conditioning demands are usually achieved using vapor compression systems pow- ered by high-grade energy. Table 1 gives operating temperatures for a variety of industrial applications (Demeter et al., 1990). If cooling and air-conditioning loads can be met through the use of waste heat (low-grade energy) from industrial * Corresponding author. Tel.: þ20 2 26333813; fax: þ20 2 26332398. E-mail address: essam_algendy@m-eng.helwan.edu.eg (E. Elgendy). www.iifiir.org available at www.sciencedirect.com journal homepage: www.elsevier.com/locate/ijrefrig international journal of refrigeration 34 (2011) 1684 e1698 0140-7007/$ e see front matter ª 2011 Elsevier Ltd and IIR. All rights reserved. doi:10.1016/j.ijrefrig.2011.01.005